1. Field of the Invention
This invention relates to the remote measurement of the properties of transparent media, such as subsurface ocean temperatures profiles, and in particular to apparatus for remotely measuring such temperature profiles from surface or subsurface vessels or aircraft.
2. Description of the Prior Art
There are several applications for remotely sensing or measuring the temperature of a bulk transparent medium such as water. One such applications is the sounding of temperature profiles in the ocean which is useful for a variety of oceanographic purposes such as measuring the depth of the thermocline, sensing internal waves, measuring heat content of oceans for meteorological applications and mapping acoustical propagation paths sensitive to temperature gradients. Insitu temperature sensors such as thermistors, thermocouples, etc. have been used in the past for these purposes but, because they are not remote sensors, are slow and awkward. A remote sensing technique in wide use is the monitoring of thermal radiation; this technique, however, is limited to measuring predominantly surface temperatures.
This invention is directed to improved apparatus for remotely measuring temperature within, i.e., below the surface of suitable transparent media or substances, as for example sea water.